A diaphragm valve includes a body (3) having a flow path (2), a seat (4) formed in the flow path (2), a metal diaphragm (5) for opening and closing the flow path (2), a pair of clamping parts (6) and (7) for claiming peripheral edge portions of the metal diaphragm (5) to fix the metal diaphragm (5) to the body (3), and an actuator (8) for abutting the metal diaphragm (5) to the seat (4) or separating the metal diaphragm from the seat (4), wherein a fluorine resin coating is formed on a seat side surface (5a) of the metal diaphragm (5) at least in a contact region (B-A) with the seat (4) in a region (C) surrounded by a clamping region (D-C) between the seat side surface (5a) and one of the pair of clamping portions (6, 7), excluding the clamping region (D-C).